Piping systems connecting floating structures to the sea bottom may be designed with a flexible catenary shape or with a near vertical configuration. Such near vertical piping systems require that a constant tensile force is maintained when the floating structure is displaced due to wind, waves and current or by warping. The varying length of the piping system due to such lateral motion must be accommodated by means of maintaining the tension as the top of the piping system moves horizontally. This may be accommodated by hydraulic equipment, by buoyancy or by other means.
At the bottom of the floating structure, the piping system requires a guiding structure which can accommodate sliding of the piping system. The piping system may also need a means of accommodating angular displacement at the bottom of the floating structure.
Current technology consists of combining rigid or flexible guide tubes with sliding metal bearings or rubber bearings which may be reinforced with metal lamella.
The current technology is illustrated by U.S. Pat. Nos. 4,185,694, 5,683,205, 6,884,003, 7,067,201, and 7,217,067.